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    Space STEM Education Guide for Global Positioning System Total Electron Content (GPS TEC)
    (2024-01-01)
    Pansong, Chollada
    ;
    Keokhumcheng, Thanapon
    ;
    Sumniang, Patiphan
    ;
    Sittichai, Wishapol
    ;
    Huang, Canjie
    This research focuses on designing a Space Science teaching model using a Science, Technology, Engineering, and Mathematics (STEM) education approach, specifically applying satellite technology in the Global Navigation Satellite System (GNSS), with an emphasis on Global Positioning System (GPS) satellites. The goal is to propose a new model in STEM education in Space Science by teaching GPS Total Electron Content (GPS TEC) variations in the ionosphere layer resulting from environmental changes on Earth, known as Lithosphere-Atmosphere-Ionosphere Coupling (LAIC). The teaching model was designed, named SPACE (S: Studying the problem, P: Planning and carrying out investigations, A: Analyzing and interpreting data, C: Critical thinking, Creative thinking, Collaborating, Communicating, and E: Evaluating, and Summarizing), serves as a guide for instructional management steps. The model was evaluated by five experts with at least 10 years of experience in Space Science. The evaluation of the appropriateness of the model for use as a teaching guideline resulted in the highest level of suitability (x = 4.87, SD = 0.40).
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    Deep Machine Learning Based Possible Atmospheric and Ionospheric Precursors of the 2021 Mw 7.1 Japan Earthquake
    (2023-04-01)
    Draz, Muhammad Umar
    ;
    Shah, Munawar
    ;
    Jamjareegulgarn, Punyawi
    ;
    Shahzad, Rasim
    ;
    Hasan, Ahmad M.
    Global Navigation Satellite System (GNSS)- and Remote Sensing (RS)-based Earth observations have a significant approach on the monitoring of natural disasters. Since the evolution and appearance of earthquake precursors exhibit complex behavior, the need for different methods on multiple satellite data for earthquake precursors is vital for prior and after the impending main shock. This study provided a new approach of deep machine learning (ML)-based detection of ionosphere and atmosphere precursors. In this study, we investigate multi-parameter precursors of different physical nature defining the states of ionosphere and atmosphere associated with the event in Japan on 13 February 2021 (M<inf>w</inf> 7.1). We analyzed possible precursors from surface to ionosphere, including Sea Surface Temperature (SST), Air Temperature (AT), Relative Humidity (RH), Outgoing Longwave Radiation (OLR), and Total Electron Content (TEC). Furthermore, the aim is to find a possible pre-and post-seismic anomaly by implementing standard deviation (STDEV), wavelet transformation, the Nonlinear Autoregressive Network with Exogenous Inputs (NARX) model, and the Long Short-Term Memory Inputs (LSTM) network. Interestingly, every method shows anomalous variations in both atmospheric and ionospheric precursors before and after the earthquake. Moreover, the geomagnetic irregularities are also observed seven days after the main shock during active storm days (Kp > 3.7; Dst < −30 nT). This study demonstrates the significance of ML techniques for detecting earthquake anomalies to support the Lithosphere-Atmosphere-Ionosphere Coupling (LAIC) mechanism for future studies.
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    A New Method for Computing Ionogram-Based TEC Based on Digisonde data for Disaster Prevention
    (2020-03-01)
    Jamjareegulgarn, Punyawi
    ;
    Duangsuwan, Sarun
    ;
    Supnithi, Pornchai
    ;
    Srisamoodkham, Worachai
    This paper presents a new approach for calculating the ionogram-based total electron content so as to be applied alternatively for alarming and preventing the disasters, for example, earthquake, tsunami or other space objectives. The proposed ITEC is estimated using the analytical expression of NeQuick model, the autoscaled Digisonde data, and a new variable "m" of 1. The results are show that 1) the proposed B0 is close to the B0-obs of Digisonde compared to the B0-IRI and the B2bot of the NeQuick model, 2) the diurnal variation of B0-Pro is the same as that of B0-obs compared to those of B0-IRI and B2bot, 3) the proposed ITEC is also close to the ITEC of Digisonde and TEC-iri, excluding the observed GPS TEC, and 4) all of the studied TEC values behave similar diurnal variations. Since the proposed ITEC is based on the analytical functions, the improvement of TEC-B0-Pro can be conducted reliably in order to close to the GPS TEC possibly and apply it optionally to correct the positioning errors for GNSS and aviation systems.
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    Comparison of GPS TEC measurements with IRI TEC prediction at the equatorial latitude station, Chumphon, Thailand
    (2011-01-01)
    Kenpankho, P.
    ;
    Watthanasangmechai, K.
    ;
    Supnithi, P.
    ;
    Tsugawa, T.
    ;
    Maruyama, T.
    We have analyzed the total electron content (TEC) derived from dual-frequency GPS receivers (GPS TEC) at the Chumpon station, Thailand, during the period 2004-2006. The diurnal, monthly, and seasonal variation in the measured TEC is compared with the TEC derived from the IRI-2007 model as well as the TEC obtained from the International GNSS service (IGS). To date, TEC data at equatorial latitudes are limited. The Chumphon station (10.72 <sup>°</sup>N, 99.37<sup>°</sup>E) is located at the equatorial latitude and the dip latitude of 3<sup>°</sup>N. The TEC from the IRI-2007 model is based on the actual F<inf>2</inf> plasma frequency (f<inf>o</inf>F<inf>2</inf>) measurement. The results of our study show that the TEC derived from the IRI-2007 model agrees with the GPS TEC data mostly in the morning hours, but that it generally underestimates the GPS TEC. The maximum differences are about 15 TECU during the daytime and 5 TECU during the nighttime. The underestimation is more evident at daytime than at nighttime. The noon-bite out phenomena are clearly seen for the IRI-2007 TEC, but not on the IGS TEC and GPS TEC. The general underestimation of the IRI-2007 model can be explained from the exclusion of the plasmasphere, whereas the large difference during noon bite-outs is caused by the difference in the slab thickness in the ionosphere between the IRI-2007 model and the actual measurement. When compared with the TEC from the IGS model, the TEC measurements at Chumpon appear to be quite similar. Copyright © The Society of Geomagnetism and Earth.
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    Variation of ionospheric slab thickness observations at Chumphon equatorial magnetic location
    (2011-01-01)
    Kenpankho, P.
    ;
    Supnithi, P.
    ;
    Tsugawa, T.
    ;
    Maruyama, T.
    This study presents the diurnal and seasonal variations of slab thickness at the equatorial magnetic latitudes in Thailand during 2004-2006, corresponding to the declining part of low solar activity. The GPS-derived total electron content (TEC) and the maximum electron density of the F-region (N <inf>m</inf>F<inf>2</inf>) are used to compute the slab thickness (&tau) at the Chumphon station (10.72<sup>°</sup>N, 99.37<sup>°</sup>E), located near the magnetic equator. The results show that large peaks of slab thickness exist during the pre-sunrise hours in all three seasons at Chumphon when compared with other latitudes. The maximum value of slab thickness occurs when the peak electron density in the F<inf>2</inf> region is at the lowest level. During daytime, the slab thickness ranges from 200 kilometers to 580 kilometers for all seasons. During nighttime, the maximum value of slab thickness is 1250 kilometers in the summer of 2004. Moreover, the diurnal variation shows two minima that appear around 0900 LT and 1900 LT, during the post-sunrise and sunset hours. The seasonal variations show that the average slab thickness daily value is greater during summer and winter than those during equinox. Our study finds that the slab thickness at Chumphon located near the equatorial latitude is much larger than those found at low, mid, and high latitudes. The difference in slab thickness between the equatorial latitude and other zones is explained by the lack of plasma flow from the plasmasphere to the F<inf>2</inf> region at the magnetic equator. Copyright © The Society of Geomagnetism and Earth.